Yang Shi [off-list ref] 于2021年9月28日周二 上午1:28写道：

IMHO I don't think this is a bug. The disparity reflects the
difference in how the page life cycle is viewed between process and
cgroup. The usage of process comes from the rss_counter of mm. It
tracks the per-process mapped memory usage. So it is updated once the
page is zapped.

But from the point of cgroup, the page is charged when it is allocated
and uncharged when it is freed. The page may be zapped by one process,
but there might be other users pin the page to prevent it from being
freed. The pin may be very transient or may be indefinite. THP is one
of the pins. It is gone when the THP is split, but the split may
happen a long time after the page is zapped due to deferred split.

Thank you for reply. I agree that it reflects the difference between
process and cgroup. The memory usage of cgroup is usually used to
indicate the memory usage of the container. It can be used to avoid
the OOM and etc. The disparity will cause that the memory usage of
containers with the same processes are randomly different (we found
more than 30GB different). It is hard to manage them. Of course,
disable THP is a way to solve it. Can it have another way to solve it
?